# Top 30 professional services firms in Nantes

Tamtam tracks 83 professional services firms headquartered in Nantes. This list ranks the 30 largest by number of employees on LinkedIn, led by Experis France, 𝗚𝗘𝗢𝗙𝗜𝗧 and Sce Aménagement & Environnement. Their median headcount is 121. Half of them were founded in 2007 or later.

These Nantes-based professional services firms are mainly mid-sized companies. Most were founded between the 1960s and early 2000s, indicating a mature business environment. The firms cover a range of specialized services, including IT, engineering, and environmental consulting.

For example, Experis France provides IT services and talent solutions, while GEOFIT designs geographical databases and manages natural resources. Sce Aménagement & Environnement focuses on sustainable development and urban planning. Bessé is an independent insurance brokerage company, and FÉTIS Group offers engineering products and services for various industries. IMATECH specializes in advanced technology solutions and digital transformation.

🇫🇷 Nantes · 30 companies · Updated Nov 12, 2026

| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [Experis France](https://www.tamtam.ai/c/experis-france) (experisfrance.fr)<br>Supports DSI with innovative digital transformation projects, providing IT services and talent solutions to enhance organizational performance, addressing specific needs. | IT Services and IT Consulting | 🇫🇷 Nantes | 2,207 |  |
| 2 | [𝗚𝗘𝗢𝗙𝗜𝗧](https://www.tamtam.ai/c/company-nantes) (geofit.fr)<br>Designing geographical databases, securing land processes for private and development projects, producing national cartography, developing agriculture, and managing natural resources. | Space Research and Technology | 🇫🇷 Nantes | 1,157 | 1968 |
| 3 | [Sce Aménagement & Environnement](https://www.tamtam.ai/c/sce-amenagement-and-environnement) (sce.fr)<br>Sustainable development firm offering urban planning, civil engineering, and environmental services globally with 45+ years of experience and 500 professionals | Environmental Services | 🇫🇷 Nantes | 625 | 1982 |
| 4 | [Bessé](https://www.tamtam.ai/c/besse) (besse.fr)<br>An independent insurance brokerage company with over 60 years of experience, specializing in protecting businesses and employees with innovative solutions and quality services | Insurance | 🇫🇷 Nantes | 610 | 1960 |
| 5 | [IMATECH](https://www.tamtam.ai/c/imatech) (ima.eu)<br>Development and integration of advanced technology solutions, software services, and digital transformation support for various industries and businesses. | Information Services | 🇫🇷 Nantes | 534 | 1999 |
| 6 | [FÉTIS Group](https://www.tamtam.ai/c/fetis-group) (fetis.group)<br>Provides engineering products and services for off-road machinery, specialized vehicles, power generation, marine power, and manufacturing industries with focus on decarbonization. | Engineering Services | 🇫🇷 Nantes | 501 | 1978 |
| 7 | [Edeis](https://www.tamtam.ai/c/edeis) (edeis.com)<br>Specializing in engineering, operation, and construction solutions for the future, this company aims to become a leader in construction services and technical management | Engineering Services | 🇫🇷 Nantes | 412 | 2016 |
| 8 | [ALTEREA](https://www.tamtam.ai/c/alterea) (alterea.fr)<br>An all-trade and energy engineering company specializing in renovation, construction, and energy optimization projects across various sectors for over 10 years | Construction | 🇫🇷 Nantes | 318 | 2004 |
| 9 | [Younup](https://www.tamtam.ai/c/younup) (younup.fr)<br>This company offers IT services, supporting clients throughout the software lifecycle from requirements to production, focusing on web, DevOps, data, AI, agility, mobile, and cloud. | IT Services and IT Consulting | 🇫🇷 Nantes | 224 | 2019 |
| 10 | [Slash Intérim](https://www.tamtam.ai/c/slash-interim)<br>Slash Intérim is a national network of temporary recruitment agents, aiming to blend human touch with digital innovation and empower independent recruitment professionals | Human Resources Services | 🇫🇷 Nantes | 203 | 2021 |
| 11 | [COCERTO](https://www.tamtam.ai/c/cocerto) (cocerto.fr)<br>Provides comprehensive accounting, audit, payroll, legal support, and digital tools to optimize and secure business operations with personalized service. | Accounting | 🇫🇷 Nantes | 200 | 1971 |
| 12 | [MECA](https://www.tamtam.ai/c/meca-nantes) (cluster-meca.fr)<br>A cluster of companies offering mechanical analysis expertise to ensure safety and feasibility of constructions through material behavior, design, and stress calculation | Business Consulting and Services | 🇫🇷 Nantes | 194 | 2006 |
| 13 | [Compas](https://www.tamtam.ai/c/compas) (lecompas.fr)<br>Specializing in social observation of territories, creating observatories, conducting studies, and providing training for local governments to address social realities effectively | Research Services | 🇫🇷 Nantes | 182 | 1996 |
| 14 | [kanoma](https://www.tamtam.ai/c/kanoma) (kanoma.fr)<br>Experts guide clients digital transformation, from design to production, focusing on agile projects, development, product design, and organizational change. | IT Services and IT Consulting | 🇫🇷 Nantes | 128 | 2018 |
| 15 | [ASENSILE](https://www.tamtam.ai/c/asensile) (asensile.com)<br>ASENSILE provides personalized professional development services for individuals and businesses, helping them navigate career challenges and reach success with a human-centered approach 🚀💼 | Professional Training and Coaching | 🇫🇷 Nantes | 121 |  |
| 16 | [EXEIS Conseil](https://www.tamtam.ai/c/exeis-conseil) (exeisconseil.com)<br>Operational consulting firm supporting organizations in mastering transformations, addressing organizational, performance, and digitization challenges across multiple industries. | Business Consulting and Services | 🇫🇷 Nantes | 104 | 2009 |
| 17 | [ELEPHANT Technologies](https://www.tamtam.ai/c/elephant-technologies) (elephant-technologies.fr)<br>Offers expert human-centered tech consultancy, ensuring perfect alignment between client needs and employee skills across various IT domains from idea to production. | IT Services and IT Consulting | 🇫🇷 Nantes | 69 | 2017 |
| 18 | [ABASE](https://www.tamtam.ai/c/abase) (generation-net.org)<br>ABASE 20 is a digital services company providing a variety of digital solutions and services to clients | IT Services and IT Consulting | 🇫🇷 Nantes | 67 | 1993 |
| 19 | [Cap-visio](https://www.tamtam.ai/c/cap-visio) (cap-visio.com)<br>assembly, installation, implementation of remote meeting and multi-site communication solutions for SMEs and large accounts in France | IT Services and IT Consulting | 🇫🇷 Nantes | 59 | 2008 |
| 20 | [CAPTEN](https://www.tamtam.ai/c/capten) (capten-group.com)<br>Offers consulting, technical assistance, and fixed-price services in IT and industry, specializing in system information and industrial project management with expert consultants. | Business Consulting and Services | 🇫🇷 Nantes | 52 | 2017 |
| 21 | [FIT Conseil](https://www.tamtam.ai/c/fit-conseil) (fit-conseil.fr)<br>FIT Conseil is a Geomatics Experts company specialized in topography, asset description, digital imaging, and land activities for development projects and asset management | Real Estate | 🇫🇷 Nantes | 52 | 1968 |
| 22 | [Mosica](https://www.tamtam.ai/c/mosica) (mosica.fr)<br>Specialized in IT strategy, architecture consulting, and tailored solutions, MOSICA helps companies transform their information systems in the digital era | IT Services and IT Consulting | 🇫🇷 Nantes | 51 | 2011 |
| 23 | [Kolibri Consulting](https://www.tamtam.ai/c/kolibri-consulting) (kolibriconsulting.com)<br>Kolibri Consulting is a Recruitment Agency specialized in Accounting and Agro-Food industries, providing personalized support to candidates and clients throughout the hiring process | Staffing and Recruiting | 🇫🇷 Nantes | 42 | 2018 |
| 24 | [RUBIX CONSULTING](https://www.tamtam.ai/c/rubix-consulting) (rubix-consulting.com)<br>Specializing in integrating SAP solutions to streamline business processes and improve efficiency | IT Services and IT Consulting | 🇫🇷 Nantes | 36 | 2019 |
| 25 | [S3d Ingénierie](https://www.tamtam.ai/c/s3d-ingenierie) (sol3d.com)<br>Independent consulting firm specializing in energy recovery from waste, offering engineering, consulting, and research services for sustainable initiatives like methanization and alternative fuels | Environmental Services | 🇫🇷 Nantes | 34 | 2007 |
| 26 | [SEIF - Zendesk Premier Partner](https://www.tamtam.ai/c/seif-zendesk-premier-partner) (seif-consult.com)<br>SEIF specializes in simplifying customer relations through expert support in implementing Zendesk tools, training, and optimizing customer experience for success | IT Services and IT Consulting | 🇫🇷 Nantes | 29 | 2018 |
| 27 | [ACII by Audensiel](https://www.tamtam.ai/c/acii-by-audensiel) (audensiel.com)<br>For over 20 years, ACII by Audensiel provides professional development support with a focus on digital transformation, IT consulting, data/AI, and cybersecurity projects | IT Services and IT Consulting | 🇫🇷 Nantes | 28 | 2000 |
| 28 | [Seyos](https://www.tamtam.ai/c/seyos) (seyos.fr)<br>Recruitment agency specializing in IT, Tech, and Industry. Acquiring and evaluating high-value talent, including rare profiles, experts, managers, and executives since 2014. | Staffing and Recruiting | 🇫🇷 Nantes | 26 | 2014 |
| 29 | [Artlex](https://www.tamtam.ai/c/artlex) (artlex.eu)<br>Established in 2004, led by 8 associate lawyers from international law firms, providing business law services in French and English nationwide and abroad Specializing in development, reorganization, and litigation support for French and foreign companies | Law Practice | 🇫🇷 Nantes | 23 | 2004 |
| 30 | [Agence Francecom](https://www.tamtam.ai/c/agence-francecom) (francecom.fr)<br>A specialized digital agency in the tourism sector, Francecom optimizes clients' digital visibility and performance through cross-channel strategies and innovative solutions | Technology, Information and Internet | 🇫🇷 Nantes | 23 | 1997 |

## How this list is built

Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Nov 12, 2026.

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- [Subscription businesses in Nantes](https://www.tamtam.ai/l/subscription-businesses-nantes) (37)
- [Financial services firms in Nantes](https://www.tamtam.ai/l/financial-services-firms-nantes) (33)
- [Real Estate companies in Nantes](https://www.tamtam.ai/l/real-estate-companies-nantes) (33)
- [Recruitment and staffing agencies in Nantes](https://www.tamtam.ai/l/recruitment-agencies-nantes) (32)
- [Advertising Services companies in Nantes](https://www.tamtam.ai/l/advertising-services-companies-nantes) (32)
- [Companies with a mobile app in Nantes](https://www.tamtam.ai/l/companies-with-mobile-app-nantes) (31)
- [Higher Education companies in Nantes](https://www.tamtam.ai/l/higher-education-companies-nantes) (29)
- [Technology, Information and Internet companies in Nantes](https://www.tamtam.ai/l/technology-information-and-internet-companies-nantes) (29)
- [Events Services companies in Nantes](https://www.tamtam.ai/l/events-services-companies-nantes) (28)
- [Critical infrastructure operators in Nantes](https://www.tamtam.ai/l/critical-infrastructure-operators-nantes) (26)
- [Professional Training and Coaching companies in Nantes](https://www.tamtam.ai/l/professional-training-and-coaching-companies-nantes) (25)

## The same list elsewhere in France

- [Professional services firms in France](https://www.tamtam.ai/l/professional-services-firms-france) (6,610)
- [Professional services firms in Île-de-France](https://www.tamtam.ai/l/professional-services-firms-ile-de-france) (3,377)
- [Professional services firms in Auvergne-Rhône-Alpes](https://www.tamtam.ai/l/professional-services-firms-auvergne-rhone-alpes) (711)
- [Professional services firms in the Hauts-de-Seine department](https://www.tamtam.ai/l/professional-services-firms-hauts-de-seine) (629)
- [Professional services firms in Provence-Alpes-Côte d'Azur](https://www.tamtam.ai/l/professional-services-firms-provence-alpes-cote-dazur) (433)
- [Professional services firms in the Rhône department](https://www.tamtam.ai/l/professional-services-firms-rhone) (400)
- [Professional services firms in Occitanie](https://www.tamtam.ai/l/professional-services-firms-occitanie) (399)
- [Professional services firms in Grand Est](https://www.tamtam.ai/l/professional-services-firms-grand-est) (316)
- [Professional services firms in Nouvelle-Aquitaine](https://www.tamtam.ai/l/professional-services-firms-nouvelle-aquitaine) (308)
- [Professional services firms in Hauts-de-France](https://www.tamtam.ai/l/professional-services-firms-hauts-de-france) (260)
- [Professional services firms in Pays de la Loire](https://www.tamtam.ai/l/professional-services-firms-pays-de-la-loire) (253)
- [Professional services firms in the Bouches-du-Rhône department](https://www.tamtam.ai/l/professional-services-firms-bouches-du-rhone) (249)
- [Professional services firms in the Haute-Garonne department](https://www.tamtam.ai/l/professional-services-firms-haute-garonne) (208)
- [Professional services firms in the Nord department](https://www.tamtam.ai/l/professional-services-firms-nord) (178)
- [Professional services firms in Brittany](https://www.tamtam.ai/l/professional-services-firms-brittany) (167)
- [Professional services firms in the Loire-Atlantique department](https://www.tamtam.ai/l/professional-services-firms-loire-atlantique) (158)
- [Professional services firms in the Gironde department](https://www.tamtam.ai/l/professional-services-firms-gironde) (151)
- [Professional services firms in Normandy](https://www.tamtam.ai/l/professional-services-firms-normandy) (114)
- [Professional services firms in the Yvelines department](https://www.tamtam.ai/l/professional-services-firms-yvelines) (108)
- [Professional services firms in Paris](https://www.tamtam.ai/l/professional-services-firms-paris) (2,241)
- [Professional services firms in Lyon](https://www.tamtam.ai/l/professional-services-firms-lyon) (265)
- [Professional services firms in Toulouse](https://www.tamtam.ai/l/professional-services-firms-toulouse) (139)
- [Professional services firms in Marseille](https://www.tamtam.ai/l/professional-services-firms-marseille) (123)
- [Professional services firms in Boulogne-Billancourt](https://www.tamtam.ai/l/professional-services-firms-boulogne-billancourt) (102)

## The same list elsewhere

- [Professional services firms in the world](https://www.tamtam.ai/l/professional-services-firms-in-the-world) (24,737)
- [Professional services firms in Europe](https://www.tamtam.ai/l/professional-services-firms-in-europe) (13,698)

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Source: https://www.tamtam.ai/l/professional-services-firms-nantes